The present invention relates generally to an improved train, and more specifically to an improved truck between the cars of integral trains and an intermodal integral train for transporting highway vehicles having their own wheels or other types of loads, without wheels, such as containers.
The designs of special cars to be used in a railroad system to carry containers or trucks or truck trailers have generally been modifications of existing railroad stock. These systems have not been designed to operate in the normal railway environment which imposes shock loads on the cars during switching and operating periods, and thus, have not taken advantage of the fact that these lighter loads could be designed for, if cars were never uncoupled for switching operations. The economy and operation of the lighter weight trains that could thus be designed, as well as economies in the cost of original material were not taken into account.
An integral train can be made up of a number of subtrains called elements. Each element consists of one or two power cabs (locomotives) and a fixed number of essentially permanently coupled cars. The cars and power cabs are tightly coupled together in order to reduce the normal slack between the cars. The reduction of the slack results in a corresponding reduction in the dynamic forces which the cars are required to withstand during the run in and out of the train slack. The reduction of the dynamic forces allows for the use of lighter cars, which allows for an increase in the cargo weight for a given overall train weight and therefore an increase in train efficiency occurs. Additional improvements in efficiency were to be obtained through the truck design and from other sources.
A complete train would consist of one or more elements. The elements could be rapidly and automatically connected together to form a single train. It is expected that in certain cases elements would be dispatched to pick up cargo and then brought together to form a single train. The cargo could then be transported to the destination and the elements separated. Each element could then deliver its cargo to the desired location. Each element would be able to function as a separate train or as a portion of a complete train. The complete train could be controlled from any element in the train. The most likely place for control would be the element at the head end of the train, but it is anticipated that in the case of a failure in the leading unit, the train could be controlled from a following element.
It is well known that when trains go around a sharp curve, the railroad truck must rotate relative to the body to allow the train to negotiate the curve. Various railroad truck constructions have been provided to allow this to happen. Similarly, articulated couplings have been provided between cars to help steer the railroad cars around the turns. These generally have included adjustable linkages connecting the cars to each other and laterally displaced to complementarily elongate and contract. In some trains, a common railroad truck has been provided between adjacent cars which constitutes the articulated coupling. The cars are joined to the truck to pivot at a point along their longitudinal axis and rods are provided at both ends of the truck and connected to each of the cars such that the axle of the truck bisects the angle defined by the adjacent lateral axis of the adjacent cars.
The truck for railroad cars generally includes a single rotating axle and a pair of wheels, as shown in U.S. Pat. No. 2,746,399. Since the axle rotates with the pair of wheels, twisting forces are transmitted between the wheels. Loads placed on the axle outboard of the wheels results in bending stresses in the axle. When the axle rotates, planes of bending forces rotate through 360.degree. at each rotation of the wheel. This subjects the outer surface of the axle to a full reverse stress cycle for each wheel revolution. This is the worst fatigue loading case and requires that the axle cross-section be round and quite heavy. At any given moment, most of the outer surface of the axle will carry stress far below the maximum stress, but will be subjected to the maximum stress at some time during the revolution of the wheel. Since wheels seldom have equal rolling radii at any two points, one wheel will tend to rotate slightly more or less than the other when a given distance is traversed. This sets up creep stresses both at the interface of the rail and wheel and at the axle. This creep is in addition to the stresses previously discussed and requires that the axle have even greater mass.
The construction of prior art trucks also requires that the trucks be removed before the wheels or axle can be replaced or maintained. This is not only inconvenient but very costly since it requires the car to be brought into a yard for maintenance.
Therefore, it is an object of the present invention to provide a lighter truck.
Another object of the present invention is to provide a truck in which the wheels are easily removed in the field.
An even further object of the present invention is to provide a truck wherein wheel wear is reduced.
Still a further object of the present invention is to provide a truck which reduces the cost of energy by reducing wheel creep.
An even further object of the present invention is to provide a truck having a better and more comfortable ride.
Still a further object of the invention is to provide a wheel and axle assembly which can be used as a driven or undriven wheel.
A still further object of the invention is to provide a wheel and axle assembly which allows maintenance of the wheel axle and its bearings in the field.
These and other objects are attained by providing a stub axle truck having a frame which carries the load between the car and the wheel instead of the axles. A pair of wheels are mounted to individual stub axles and each of the stub axles are rotatably mounted to the frame. Springs are mounted to portions of a lateral frame member extending beyond longitudinal frame members. This allows the movement in the truck lateral frames to be as low as possible, thus minimizing the cross-sectional dimension and weight of the load members. A pin is connected to and centered on the frame for rotatably connecting the frame to the longitudinal axis of the car.
The frame includes two lateral or transverse members with two pairs of longitudinal members connected at each end thereof. Inverted U-shaped openings in the longitudinal members receive the stub axles and bearings which rotatably mount the stub axles within the U-shaped openings. A retainer is provided at the bottom of each U-shaped opening for removably retaining the axle and limiting the axial movement of the bearings. This particular structure allows easy removal of the wheel, the stub axle and bearings in the field by merely raising the truck, removing a portion of the retainer which extends across the bottom open legs of the U-shaped opening and then dropping the wheel bearings and axle.
The stub-axle is hollow and includes a sleeve extending through it. A pair of radial flanges extend from each end of the sleeve for mounting the bearing to the axle. One of the radial flanges is removable to allow disassembly of the bearing from the axle. The removable radial flange and the sleeve include mating threaded surfaces. Axially extending and mating recesses and lugs are provided on the end of the axle and on the non-removal flange to interlock them to prevent rotational movement therebetween. The sleeve includes splines on its interior for mating with the splines of a drive shaft. Thus the axle can be used for driven and non-driven wheels using a sleeve.
In another embodiment, the radial flanges are mounted directly to the axle of the wheel to act as bearing retainers. They are removably secured thereto by fasteners. In a power driven stub axle a shaft traverses the axle and connects to the power train. On the outboard side, this axle is connected to the outboard radial flange so as to drive the axle through the outboard radial flange.
In a power driven stub axle truck, a gear box is connected to the pair of wheels by a pair of drive shafts. The center pin may be connected to the gear box versus the frame. The outer diameter of the coupling between the gear box and the drive shaft is smaller than the outside diameter of the coupling of the drive shaft and the sleeve. This allows removal of the drive shaft axially through the axle without removing the axle from the frame. A cap on the end of the axle seals the connection of the sleeve and the drive shaft and includes a structure biasing the drive shaft towards the gear box. A biased seal is provided on the sleeve on the other side of the connection of the drive shaft to the sleeve. Also a biased seal is provided on the drive shaft to seal the connection of the drive shaft to the gear box. The outside diameter of the coupling at the gear end of the drive shaft and the sealing on the drive shaft is smaller than the inside diameter of the sealing on the sleeve.
The use of a spline connection between the drive shaft and the gear and the axle allows for deflection. The pin connecting the gear box or frame to the car body increases the stability and transferring of loads between the frame and the body and removes the requirement for lateral stops of the wheels relative to the frame.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.